1. Field of the Invention
The invention concerns electromagnetic wave guides comprising a hollow conductor externally covered with a casing.
2. Description of the Prior Art
Generally the casing is formed by surrounding the hollow conductor of the wave guide with successive layers of dielectric materials, for example fibre glass or conductive taping, for example taping with woven copper gauze or steel strips. These successive layers are bound together and to the hollow conductor by a resin which is polymerisable when hot.
The hollow conductor is fragile and easily deformable, for it is generally made either with a metallic wire wound in a spiral or with a thin metallic tape folded in the form of a tube. Despite all the care taken in manufacturing the wave guide, it is impossible to prevent the hollow conductor from undergoing deformation during the heat treatment necessary for hardening the resin. These deformations are very detrimental to the quality of the transmission of the electromagnetic waves.